I've had the MX-810 for 2 days now.
This is a GREAT remote. I don't know why some CI are so hard on it.

The software is quirky and in some cases buggy, but everything else is wonderful.
FYI, I'm upgrading from an old Pronto TSU1000.

I had my initial setup working in less than 1 hour. Very simple to set up.
It took a call to Surf (thanks!) and another couple of hours of tweaking and
I couldn't be happier.

FYI, I was able to use the Universal Browser to import some commands directly
from my Pronto CCF. The browser even displays my pronto screen. Very cool.

As far as your ANT issue?
I had similar problems with inputs and I used both toggle and discreet.
This may or may not be the problem for your setup, but this is what I found:
Do not list ANT as an input for the TV device.
If, for example, you have ANT + 3 inputs, define the three inputs
"Vid 1", "Vid 2", and "Vid 3"

When you initially create your OTA activity it will not have a command to switch
to ANT, because it doesn't know about the ANT input.
You can then Tune the activity and add a step.
The last step to add is copied from the TV Device and is the "ANT" button.
Or you can add the step in the Browser.

Also, I have a bug with OTA HD channel commands say for channel "8.1"
First I had to teach the "dot" command to the 10+ button of the device.
Second, no matter what I did the digit after the "dot" was not transmitted
correctly by the remote. I have IR flashers, so I could see something was
sent for the last digit, but it WOULD NOT WORK.
So, I finally figured out a workaround by programming the number as "8.11"
This would correctly detect the final digit.

I was going to wait for the R70 because I don't need the RF, but I'm glad I didn't.